4. Spending time in your social circle enhances recovery after intense stress.

5. Sleep and rest

“Hours 7 to 9 – the hours that the majority of us never get – are actually the most powerful.”

Anabolic hormones: “You can get more of the same hormones that countless athletes have risked their health, reputations, and careers for (by injecting synthetic steroids, aka doping) simply by sleeping for a few additional hours.”

“If we never take “easy” periods, we are never able to go full throttle and the “hard” periods end up being not that hard at all.”

6. ‘Feeling good’ increases testosterone, and thus performance.

“Perhaps, more than any other hormone, testosterone is linked to performance. It increases muscle growth, strength, and energy.”

Dave Hamilton, Director of Performance Science for the US Women’s field hockey team. “Without fail, he hold us, testosterone levels were highest when his athletes felt good.

Micheal Joyner, MD “You need to say no to a lot of things so that when it’s time to say yes, you can do so with all your energy.”

8. Motivation (good or bad) spreads through tight-knit groups like a disease.

Over 4 years in the United States Air Force Academy, “the determining factor as to whether the 30 cadets within a squadron improved was the motivation of the least fit person in the group. If the least fit person was motivated to improve, then his enthusiasm spread and everyone improved. If, on the other hand, the least fit person was apathetic or, worse, negative, he dragged everyone down.”

In the face of challenge, apathetic or negative peers “exploits and amplifies preexisting doubts one might have.”

9. Your social circle influences your own behavior.

“Studies show that if one of your friends becomes obese, you are 57 percent more likely to become obese yourself.”